Studies at the basic and clinical level continue in several heritable bone disorders and the mucopolysaccaridoses. Purification of the enzyme iduronate sulfatase, the enzyme deficient in the Hunter Syndrome, continued. A clinical study of the use of human amnion membrane implantation into children with the MPS disorders has been completed with the conclusion that the procedure is not effective in either clinical or biochemical correction in several of the MPS conditions. Several clinical findings emerged from the study, including an awareness of the extent of hydrocephalus in the MPS population and the existence of retinal degeneration. The procedures used in patient evaluation should provide appropriate clinical guidelines for subsequent attempts at therapy. Studies of the use of 13-cis retinoic acid in the treatment of fibrodysplasia ossificans progressiva continue with some 14 patients now being treated. Preliminary studies have revealed the presence of markedly elevated blood prostanoids (PGE2) in all patients with FOP. The nature of this compound is under study. Studies in osteogenesis imperfecta continue. Fibroblasts and blood have been collected on several pedigrees to provide material to begin molecular genetic analysis of Type I collagen polypeptides. Studies were continued to determine the structure of the transcriptional unit in bone and fibroblasts for one of the Type I polypeptide genes. Clinical studies on O.I. underway include the use of bracing in infants with O.I. and regulation of the growth hormone axis in the condition.